let num = 2

// switch 是 === 严格类型比较
switch (num) {
	case 1:
	case 2:
	case 3:
		console.log('num is 1, 2 or 3')
		break

	case 4:
		console.log('num is 4')
		break

	default:
		console.log('啥也不是~')
		break
}
